(1) Field of Invention
This invention relates to a vidicon camera adapted for use in a closed circuit television system and in particular to a small, compact vidicon camera mounted in a housing adapted to be connected by a coaxial cable to a remote television system. The vidicon camera is remotely located from the video processor and other components of a closed circuit television system. The present invention has utility for use in a television microscope system wherein the video camera is attached directly to a microscope. A microscope may be used for viewing small articles or a selected small field of vision such as in a medical operation. The microscope produces an optical image which is directed onto the imaging surface of the vidicon camera by a lens system. The vidicon camera converts the optical image into a composite video signal having chrominance signals representative of the optical image. The composite video signal is used in a closed circuit or direct wire television system for producing a colored television picture which is representative of the optical image being viewed by the microscope.
(2) Description of the Prior Art
Small compact video cameras adapted for use in a direct wire television system are known in the art. In one known vidicon camera, camera housing encloses a vidicon tube, horizontal and vertical deflecting coils, focusing controls, filters, preamplifier and amplifier and a video processor. The output of the video camera is an amplified processed composite video signal capable of being applied directly to a television monitor, television receiver or video recorder. In such a device, the video camera is of fairly large size in order to enclose all of the components as described above. The size of such a video camera is large relative to the size of a microscope. Because of the size of such video cameras, it is cumbersome to attach, connect or otherwise position a video camera relative to a microscope or other similar instrument to receive the optical image.
Another disadvantage of a known prior art is that the video camera normally includes a video processor which functions to produce a composite video signal which is adapted to be directly applied as an input to a television monitor, television receiver, or video recorder. In addition, integral with the video camera are the electronics and controls for controlling horizontal and vertical deflection coils and the focusing coils. The inclusion of a video processor, video processor electronics and control electronics for the horizontal and deflection coils and focusing coils results in increased size and weight of the camera.
It is also known in the art to separate the video processor from the video camera head and to interconnect the same with direct wire, coaxial cable or other similar electrical connecting means. In such devices, the video camera head is still of relatively large size for ease of use with certain applications. Such known video cameras generally have deflection circuits and other control circuitry within the camera housing thereby imposing a limit on how small the housing can be to enclose the camera components.
The ease and the ability to use a video camera in connection with laboratory or medical instruments which generate an optical image are limited directly by the size and weight of such a video camera. For example, an endoscope may be used for exploring the interior of a human body. An optical image representing the small field of view is displayed by means of a lens system in a viewer. A physician observes, through the viewer, the small interior area of the body viewed by the endoscope. By attaching or connecting a video camera to the endoscope, the optical image can be displayed in a television monitor or recorded on a video recorder.
Another disadvantage of the presently known video cameras is that a relatively large electrically connecting cord is required between the video camera and the television system for displaying the television image picked up by the video camera. The large electrical connecting cable becomes difficult to maneuver and has a limited degree of flexibility in an operating room or laboratory experiment.
In addition to medical application, there are numerous other applications which utilize video cameras for viewing images through microscopes. Such applications include assembly and wiring of integrated circuits, assembly of precision electronic components and for making measurements of microscopic objects. In such applications, it is desirable to display and/or record a video representation of the optical image for a number of purposes. One purpose is to reduce or eliminate eye fatigue of an observer or technician performing the examination and/or test work. In such applications, the size of the video camera limits the practicability and the type of environment in which such a television microscope system can be used.
There are large numbers of presently known closed circuit television systems wherein a video camera is remote from the television receiver, television monitor or video recorder wherein the video camera is used to utilize optical images developed from a variety of instruments. In such applications it is highly desirable to have the actual pick up video camera head be as small, compact and light weight as possible. The presently known video cameras generally have a weight in the order of 3 lbs. (1.36 kg) or more and have dimensions which are in the order of approximately 6" (15.4 cm) in length, 6" (15.4 cm) in height and 4" (10.26 cm) in width and enclose substantially all the electronics and controls necessary to enable the video camera to operate as a separate independent device.